Isnt it just a picture of Fiat 126p in one of polish villages ? I mean, there is nothing special at all to sell it for (!) 300USD. Come on, try a little bit harder...
Those are graphite drawings (Aedes Aegypti) and a picture below, the art come along with its mounting and certificate.
In the other matter, Artists decide if they want to print their idea on a graphite drawing, oleo paint or a picture, they are famous, they put their prices and there is alot of people willing to pay for them. Have a nice day.